Comparison to Greasemonkey

It is often compared to Greasemonkey,
another Mozilla extension that allows for the client-side
manipulation of web pages through userscripts, or client-side
JavaScript. Furthermore, the website of the extension, which hosts
a gallery of user-created stylesheets, also allows for the option
of installing a webpage stylesheet as a userscript through
Greasemonkey.

Examples

Below are some examples of Stylish user styles
being applied to web pages.